Refineries include a large number of processing steps to make a wide variety of hydrocarbon products. These facilities are very versatile, enabling them to vary the product slate to accommodate changes in season, technologies, consumer demands and profitability. Hydrocarbon processes are varied yearly to meet seasonal needs for gasoline in the summer months and heating oils in the winter months. Availability of new polymers and other new products from hydrocarbons causes shifts in product distributions. Needs for these and other petroleum-based products results in continuously changing product distribution from among the many products generated by the petroleum industry. Thus, the industry is constantly seeking process configurations that produce more of the products that are higher in demand at the expense of less profitable goods.
Most new aromatics complexes are designed to maximize the yields of benzene and para-xylene (“p-xylene”). Benzene is a versatile petrochemical building block used in many different products based on its derivation including ethylbenzene, cumene, and cyclohexane. Para-xylene is also an important building block, which is used almost exclusively for the production of polyester fibers, resins, and films formed via terephthalic acid or dimethyl terephthalate intermediates. Thus, the demand for plastics and polymer goods has created a need in the refining industry for generation of large amounts of aromatics, including benzene, xylenes, particularly p-xylene, and other feedstocks for an aromatics plant.